Accretion definition, an increase by natural growth or by gradual external addition; growth in size or extent. See more.
Alveoli are tiny sacs within our lungs that allow oxygen and carbon dioxide to move between the lungs and bloodstream. Learn more about how they function and quiz your knowledge at the end.
Rating Newest Oldest. Best Answer: The alveoli of the lungs are epithelial cells. Go to http://en.wikipedia.org/wiki/Alveolar-ca... to get a better understanding of the functional level of lung tissue. There are also various connective tissues which make up the airways that lead to the alveoli. Ventilation [how air goes in and out of the lungs... Good luck and happy learning!